A second day of stifling heat and humidity caused havoc at the U.S. Open on Tuesday, prompting tournament organisers to implement special rules to provide relief for suffering players.
With temperatures soaring above 90 Fahrenheit (32C) amid crushing humidity, the United States Tennis Association (USTA) said the 10-minute heat break that women players are granted between the second and third sets would be extended to the men.
"Upon the recommendation of the U.S. Open medical team, the Extreme Heat Policy will be implemented immediately for men's matches," the USTA said in a statement.
"The men will be offered a 10-minute break between the third and fourth set.
"The Tournament Referee, along with the medical team, will continue to monitor on-site conditions, to determine when the Extreme Heat Policy will no longer be in effect."
At least two players retired from first-round matches on Tuesday due to the heat, said USTA spokesman Chris Widmaier.
"Everyone always talks about how hot Melbourne is but the US Open's way worse," 2011 US Open champion Samantha Stosur of Australia said after her first-round loss.
In his post-match briefing, after beating Marton Fucsovics 6-3, 3-6, 6-4, 6-0, Novak Djokovic said it was a "magnificent feeling" when he and his US Open first round opponent Fucsovics sat naked in separate, adjacent ice baths during a heat break on Tuesday.
Djokovic and Hungary's Fucsovics spent their brief time off court at the Arthur Ashe Stadium by stripping down and plunging into ice baths to cool off from the 38-degree heat.
"I want to thank US Open for allowing us to have a 10 minute break. I think we both needed it," said Wimbledon champion and two-time US Open winner Djokovic.
"We had the ice baths next to each other. We were naked in the ice baths -- it was a magnificent feeling I must say to be naked with the guy you are still battling when the match hasn't finished."
No relief was in sight as hot temperatures and humid air were expected at the tournament again on Wednesday.
Seventh-seeded Croat Marin Cilic called the conditions brutal and said they were made worse by the introduction of a shot clock this year to speed up play.
"You have in mind that you are under the shot clock so it's not easy to prepare even after some long rallies," he said after his first-round victory.
Earlier on Tuesday, a fan collapsed in the stands at the sun-exposed court 17 during Czech Petra Kvitova's win over Yanina Wickmayer, causing the chair umpire to halt play while emergency medical personnel attended.
Elsewhere, fans crowded into the shady sections of the tournament's two stadiums and fanned themselves furiously while taking in the first-round action.
Organisers urged everyone attending the 50th edition of the tournament in Flushing Meadows Park to drink plenty of water and use sunscreen to protect themselves.
Yet they said they would not close the roof on either of the two stadiums due to the heat.
The new 14,000-seat Louis Armstrong Stadium does not have an air conditioning system but relies on a unique natural ventilation system, which will be severely put to the test.
The roofs on the Arthur Ashe and Louis Armstrong stadiums will likely be shut on Friday, however, as rain is forecast which is expected to bring relief from the heat. It could also throw a wrench in the tournament's busy schedule.
As for the players who have to cope with the sweltering conditions, it is all part of the brutal test that is the fourth and final Grand Slam of the year.
"It's one of the reasons the US Open is the toughest test in tennis," Widmaier told Reuters.
Several players requested medical attention due to the heat during their matches on Monday while some on the women's side opted to take advantage of the 10-minute heat break.